Dust collecting apparatus for use with grinding wheels



fiw Inn March 21, 1950 Filed Sept. 11, 1946 W. MULLER DUST COLLECTING APPARATUS FOR USE WITH GRINDING WHEELS 3 Sheets-Sheet l WWW/4% March 21, 1950 w. MULLER 2,501,287 DUST COLLECTING APPARATUS FORYUSE A WITH GRINDING WHEELS Filed Sept. 11, 1946 3 Sheets-$he et 2 W III I V 6' I Fl 23 "a o 3 A 45 6A9 10 x Il i March 21, 1950 ,w. MULLER 2,501,287

- DUST COLLECTING APPARAT? FOR USE WITH GRINDING WHE LS Filed Sept. 11, 1946 5 Sheets-Sheet. s

Patented Mar. 21, 1950 DUST COLLECTING APPARATUS FOR USE WITH. GRINDING WHEELS Wilhelm Muller, Sheffield, England, assignor or one-third to Paul Richartz and one-third to Stephan Richartz, both at SheflielmEngland Application-September 11, 1946, Serial No. 696,320 In Great Britain July 4, 1945 7 Claims.

This: invention relates to dust-collecting apparatus for use" with grinding wheels, buffing wheels, and like rotating, abrading and polishing heads, and of the kind in which therotating head is partly encircledby a hood or casing having associated therewith a conduit and means for inconnected therewith by a short space or conduit .so that there is a minimum resistance to flow of the air-stream therein and in that said hood and/or head is-so constructed and arranged that the rotation of the head induces a flow of air through .said' space or conduit, and so as to produ-ce an air stream around said hood or casing in substantially a closed circuit. Heretofore, it has been usual for the dust separator to be located at a considerable distance away from the hood, for example, outside the room where the heads are operating, and thus a considerable drag has been imparted to the air by the conduit, necessitatingv the provision of a separately driven impellor. The arrangement according to the present invention renders such a separately driven impeller unnecessary. There may, however, be associated with the rotating head, an-impellor or the head may be iormed so as to increase the flow of air.

An important feature of the present invention consists in providing in a dust-collecting apparatus of the kind referred to above, means for conveying theair leaving the separator back again to the neighborhood of the hoods It has been found in an arrangement in which the hood. surrounds .both the. upper and lower parts of the rotating: head, but-leaving a gap through which access to the head may bev obtainedglthat. the most: effective location for reintroducing the air into. the head is on that side of said gap which is last traversed by any point on the. periphery of the head. Preferably, the conduit for conducting the air back again into the gap is directed in the direction of rotation of the s s rhe e i a i th we so a t Pr ven unwanted turbulence of the air as it. passes into the hood. It will be appreciated with the-above arrangement, that since the air is being continuously circulated through the apparatus, there is little tendency for additional air to be drawn in through the hood, and thus objectionable draughts are avoided.

The following is a description of one form of the invention as applied to a polishing bufi, reference being made to the accompanying drawings, in. which:

Figure l is a perspective view of the apparatus;

Figure 2' is a vertical section;

Figure 3 is a plan, and I Figure 4 is a. section on the cranked line 4-4 of Figure 2.

As will be seen from Figure 2, the upper part of the rotating head or polishing bufi i0 is, enclosed by a two-part casing II, [2, which parts are so spaced away from the. periphery of the buif that the radial. width. of the gap between the periphery and the casing, part II is substantially constant, while the radial width between the. periphery and the other part l2 of the casing diminishes in the direction of rotation ofthe bud, shown:v by the. arrow.

The side walls [5 of thecasing part l2v converge as, they extend forwardly, as best seen in Figures 1 and. 3. This arrangement promotesa high velocity stream of air directed downwardly from the lip 16 of the casing. part l2, and car-.

rying with it any fluff or dust resulting from the polishing operation.

The. lower part of the buff is flanked by side walls each formed, in a rear part I! and a forward part 18. The rear parts I! constitute continuations of the side walls of the casing part II and are provided with guide-ways [9 for slidably en: gaging a beading formed on the lower edges of the casing part l2. The forward side parts l8 diverge.

Disposed on the outside of each of the two part side walls l'l, i8, is a conduit 21. which extends upwardly and rearwardly from the lower end 01 the side wall part l8 and communicates through aniopening 22 (see Figure 2) in the sidewall part II with the space between casing part I I and the buff; Disposed between the side wall parts [7 above the'opening 22 is a forked plate 23 which straddles the buii and is radially adjustablev on a bridging wall 24 extending between parts of the conduits 2! which project beyond the rear part of the casing H. The plate 23 is retained in its adjusted position by a clamping nut and bolt 25".

or other clamping means, the latter of which is fixed to the bridging wall and extends through a slot in the plate and through a hole in a flexible strut 26 fixed to the bridging member.

The assemblage so far described is arranged over an upright cylindrical casing-21 and is secured thereto by a circular plate 28 to the upper side of which the side wall parts I! and I8 are attached and the rear wall 29 extends between the two conduits 2!. The circular plate is cut away to provide an opening between the side wall parts IT, IS and is also provided with openings 3| (see Figure 4) registering with lower ends of theconduits 2|.

The circular plate is provided with lugs 32' which are clamped by bolts 33 to lugs, 34 on the cylindrical casing 21.

The side wall parts 18 are formed with flanges 35 at their lower edges which are bolted to the circular plate. The cylindrical casing is provided with slotted angle pieces 36 by which it may be bolted to a supporting base or frame 31 as shown in Figure 2.

Rotatably mounted in the cylindrical casing is a. cylindrical wire mesh basket 38 open at its top and having a closure plate 39 at the bottom to which is fixed a boss 40 keyed to a shaft 4! driven by a motor 42. The motor is also arranged to drive the buffing wheel through suitable gearing 43. Alternatively, the motor may drive the builing spindle direct and a suitable transmission is provided between the buffing spindle and the shaft 4|.

The cylindrical casing 21 is provided with a forward extension 44, one ofthe sidewalls 45 (which is a leading wall with respect to the direction of rotation of the wire mesh basket 38 as shown by the, arrow in Figure 4) being arranged tangential to the casing 21 while the other side wa l 45 is non-tangential so as to tend to gather the air stream induced by the rotation of the basket. The bottom wall 41 is curved upwardly and outwardly. Secured over the upwardly directed spout 50 thus formed is a shroud having an upwardly and rearwardly curved front wall 48 (see Figure 2) secured between side walls 49 which form continuations of the side wall parts l8. Also secured between the side walls 49 is a rearwardly and downwardly inclined upper wall which meets the top face of a part 52 of the circular plate 28 and overlaps the upper wall 48 on the underside thereof to provide a gap 557 The wall 48 overlaps the wall 41 and is secured thereto by a clamping bolt 56. A deflecting plate 53 on the underside of the part 52 forms an extension of the upper wall 5! and projects over the top of the basket 38. A suflicient gap, indicated generally at 54, is provided between the lip "5 of the casing part I2 and the side walls [8, 49 and upper wall 48 to permit the article to be buffed to be brought into contact with the buffing wheel.

- Thus air directed through the gap 55 and along the plates 51, 52 is arranged to flow substantially tangentially to the periphery of the buif, thereby preventing eddy currents being set up in the gap 54.

With the above arrangement the downwardly directed high velocity air stream promoted by rotation of the buff in the converging part of the 4 cling to the sides of the bufling wheel flows along the side walls I! and I8 until it meets the underside of the plate 23. Due to the centrifugal action of the air stream the majority of the dust and fiufl will be on the outside and will thus strike the plate and be deflected through the openings 22 into the conduits 2|. It will pass down the conduits through the openings 31 at the bottom into the basket.

The air passing upwardly between the periphery of the bufi and the forward edge of the plate 23 will be more or less dust and fluff free, and will again be delivered past the lip [6 in the form of upper casing I2 entrains in it any dust and fluff resulting from the buffing operation. The greater part of the dust and fluif laden air is then directed by the inclined upper wall 5| and its continuation into the rapidly rotating wire mesh basket 38, while the remaining air which may a high velocity air stream. The dust and fluff laden air which is delivered into the wire mesh basket will be filtered by centrifugal action and the filtered air will Pass up the spout 50 through the gap 55 and will then be partly deflected down into the basket again and partly around the wheel and past the plate 23. Thus, there are promoted two substantially closed ci'rculating air streams, one by the rotation'of the buff; and the other by the rotation of the wire mesh basket, which st-cams at one point merge with one another. Thus, there is little or no tendency for outside air to be drawn through the opening 53 where the operator is situated.

The quantity of air circulatingwith the buff 10 may be controlled by the adjustment of the plate 23. i

As indicated earlier in the specification, the buif or shaft driving the buff may be provided with an air impeller for increasing the how.

I claim:

1. A dust collecting apparatusfor a machine having a rotating wheel for treating work,comprising a hood surrounding the wheel but formed with a gap through which the work may be brought into contact with the wheel which hood is so shaped to provide a space between the periphery of the wheel and the surrounding part of the hood which space diminishes both in radial dimension as it extends in the direction of rotation towards said opening and also so as to Drovide a space between the sides of the wheel and sides of the hood which diminishes axially as the space extends towards the opening and at least one of which sides of the hood is provided with an aperture on the opposite side of the axis of rota tion to said gap, a closed chamber beneath said hood. the top of said chamber communicating with said hood below said gap, a dust separator in said chamber and a conduit leading from said aperture into said closed chamber.

2. A dust collecting apparatus for a machine having a rotating wheel for treating work, com-' prising a hood surrounding the Wheel but formed with a gap through which the work may be brought into contact, with the wheel which hood is so shaped to provide a Space between the periphery of the wheel and the surrounding part of the hood which space diminishes both in radial dimension as it extends in the direction of rotation towards said Opening and also so as to provide a space between the sides of the wheel and sides of the hood which diminishes axially as the space extends towards the opening and eachof which sides of the hood is provided with an opening on the opposite side of the axis of rotation to said gap, a closed chamberbeneath said hood. the top of said chamber communicating with said hood below said gap, a dust separator in said chamber and conduits leading from said apertures into said closed chamber, a conduit extending laterally of said closed chamber beneath said gap and having a nozzle at its extremity directed inwardl towards said gap.

3. A dust collecting apparatus for a machine having a rotating wheel for treating work, comprising a hood surrounding the wheel but formed with a gap through which the work may be brought into contact with the wheel which hood is so shaped to provide a space between the periphery of the wheel and the surrounding part of the hood which space diminishes both in radial dimension as it extends in the direction of rota.- tion towards said opening and also so as to provide a space between the sides of the wheel and sides of the hood which diminishes axially as the space extends towards the opening and each of which sides of the hood is provided with an opening on the opposite side of the axis of rotation to said gap, a closed chamber beneath said hood, the top of said chamber communicating with said hood below said gap, a dust separator in said chamber and conduits leading from said apertures into said closed chamber, a conduit extending laterally and upwardly from said closed chamber beneath said gap and having a nozzle at its extremity directed inwardly and along the inclined top wall of the conduit, and the wall of which hood which encircles the periphery of the wheel as to the part thereof immediately above the gap, tangentially disposed to the head.

4. A dust collecting apparatus for a machine havin a rotating wheel for treating work, comprising a hood surrounding the wheel but formed with a gap through which the work may be brought into contact with the wheel which hood is so shaped to provide a space between the periphery of the wheel and the surrounding part of the hood which space diminishes both in radial dimension as it extends in the direction of rotation towards said opening and also so as to provide a space between the'sides of the wheel and sides of the hood which diminishes axially as the space extends towards the opening and each of which sides of the hood is provided with an opening on the opposite side of the axis of rotation to said gap, a closed chamber beneath said hood, the top of said chamber communicating with said hood, a dust separator in said chamber, conduits leadin from said apertures into said closed chamber, and a bafile disposed in the space between the hood and wheel at a location above the apertures in the side walls of the hood.

5. A dust collecting apparatus for a machine having a rotating wheel for treating work, comprising a hood surrounding the wheel but formed with a gap through which the work may be brought into contact with the wheel which hood is so shaped to provide a space between the periphery of the wheel and the surrounding part of the hood which space diminishes both in radial dimension as it extends in the direction of rotation towards said opening and also so as to provide a space between the sides of the wheel and sides of the hood which diminishes axially as the space extends towards the opening and each of which sides of the hood is provided with an opening on the opposite side of the axis of rotation to said gap, a closed chamber beneath said hood, the top of said chamber communicating with said hood below said gap, a dust separator comprising 6. A dust collecting apparatus for a'machine having a wheel rotatable about a horizontal axis which apparatus comprises a hood surrounding the wheel but formed with a gap through which the work may be brought into contact with the wheel which hood is so shaped to provide a space between the periphery of the wheel and the surrounding part of the hood which space diminishes both in radial dimenslon as it extends in the direction of rotation towards said opening and also so as to provide a space between the-sides of the wheel and sides of the hood which diminishes axially as the space extends towards the opening and each of which sides of the hood is provided with an opening on the opposite side of the axis of rotation to said gap, a closed chamber beneath said hood, the top of said chamber communicating with said hood below said gap, a dust separator comprising a rotating open topped air permeable basket, rotatable about an upright axis and conduits leading from said apertures and directed into the top of .said basket.

7. A dust collecting apparatus for a machine having a wheel rotatable about a horizontal axis which apparatus comprises a hood surrounding the wheel but formed with a gap through which the work may be brought into contact with the wheel which hood is so shaped to provide a space between the periphery of the wheel and the surrounding part of the hood which space diminishes both in radial dimension as it extends in the direction of rotation towards said opening and also so as to provide a space between the sides of the wheel and sides of the hood which diminishes axially as the space extends towards the opening and each of which sides of the hood is provided with an opening on the opposite side of the axis of rotation to said gap, a closed upright cylindrical chamber beneath said hood, the top of said chamber communicating with said hood below said gap, a centrifugal dust separator comprising an open topped air permeable upright cylindrical basket, means for rotating said basket about its axis and conduits leading from said apertures and directed into the top of said basket.

WILI-IEILM MULLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

